1. Field of the Invention
The present invention is related to radiation control of a portable electronic device, and more particularly, to an apparatus for controlling electric field distribution.
2. Description of the Prior Art
As the electronic circuit technology continues to develop in recent years, a variety of wireless communication functions are widely implemented in many applications. Therefore, the radiation control for these wireless communication functions becomes a very popular topic. Certain regions and countries of large product sales tend to have some regulations for products on the market. For instance, the product with the Federal Communications Commission (FCC) certification should comply with the relevant specifications when on the market. Similarly, the product labeled with Conformité Européenne (CE) should comply with relevant regulations when on the market.
According to the related art, the typical examples of the radiation-related indicators include: indicators of radiation energy absorbed by the body, especially the so-called specific absorption rate (referred to as “SAR value” hereinafter); and indicators of radiation energy interfering with hearing aids, especially the so-called hearing aid compatibility (referred to as “HAC value” hereinafter), wherein the measurement results of the SAR value and the HAC value tend to be affected by the total radiated power (referred to as “TRP value”) in the wireless devices over the air performance (referred to as “OTA performance”), and the energy distribution of wireless devices.
The conventional solutions, such as reducing the OTA performance, attaching, using expensive absorbing materials or metal materials, etc., are frequently used in a variety of wireless devices to satisfy the related specifications of the HAC value and the SAR value, especially to enhance the HAC value and to reduce the SAR value. The conventional solutions often cause side effects, for example, resulting in poor communication quality, increasing cost and reducing design flexibility. Therefore, there is a need for a novel architecture for controlling surface current distribution of a wireless device to improve the performance of the wireless device in the HAC value and the SAR value by concentrating the electric field distribution of wireless devices on the antenna region.